Well packer and anchor means therefor



Sept. 1, 1970 L. B. SCOTT WELL PACKER AND ANCHOR MEANS THEREFOR Filed June 10, 1968 Z Fm 1a.

3 Sheets-Sheet 1 I Q/ 7 C4 5&4 58 50b 7 50 v 366 65 5 9d INVENTQR. 9 0 45 15. scarf Sept. 1, 1970 L. B. SCOTT WELL PACKER AND ANCHOR MEANS THEREFOR Filed June 10, 1968 3 Sheets-Sheet 2 A TTOEA/EV 0 A/v 4 06 5 d 7 R w e g @wmvfimw w4 ww aywaa we m7 1 9 7 5 0 W 4 i /0 0 a c W m a a 2? 5 6 2 rw 5 7 5 4 25/ a 4 E m w w 3a55 4 w 3 1 1 [VP t if... M I a d z MW v l1 1 0 5 ii n map A w a Sept. 1, 1970 B. SCOTT WELL PACKER AND ANCHOR MEANS THEREFOR Filed June 10, 1968 S Sheets-Sheet 8 Ill-Ill INVENTOR. was 5 66077 (4 TU A 6V United States Patent U.S. Cl. 166121 15 Claims ABSTRACT OF THE DISCLOSURE Anchoring mean for well bore tools, in which an expander has oppositely facing conical surfaces which cooperate with a pair of spaced apart sets of slip elements which are independently outwardly movable into anchoring engagement with the well wall, the expander being on a mandrel which slidably supports the slip elements, and a tie member being disposed within the mandrel and spanning the expander to hold the slip elements against relative movement longitudinally of the mandrel, the mandrel being longitudinally shiftable relative to the tie member to effect anchoring engagement with the slip elements of one set or the other depending upon the direction of movement of the mandrel.

Such an anchoring means in a retrievable well packer having control means for running and retrieving the packer with said expander centralized between the sets of slip elements, the control means being operable to allow movement of the mandrel of the well packer in either longitudinal direction to anchor the packer against movement in either direction alternately.

BACKGROUND OF THE INVENTION Field of the invention In certain treatments of subsurface earth formations traversed by a well bore, it is desirable to set within the well bore a packer or bridge plug device which may be run into the well bore on a wire line or on pipe and set in place so as to provide a seal bridging the well conduit whereby fluids may be injected into the well conduit and displaced therefrom into subsurface earth formations located at an elevation above the bridge plug. At other times, such packers or bridge plugs are employed to hold subsurface pressure within the well beneath the packer.

Such bridge plugs and packers are required to remain anchored in a well bore notwithstanding the presence of differential pressure thereacross from either direction, that is, notwithstanding high pressure below the bridge plug or packer on the one hand, or high pressure above the bridge plug or packer on the other hand. Typically, bridge plugs and packers required to have a double holding capacity involve the use of slip elements cooperative with a conical expander surface to anchor the tool against upward movement in the well casing in the event that the high pressure is below the tool and another set of slip elements cooperative with another conical surface adapted to anchor the tool against downward movement in the well casing in the event that it is subjected to high pressure above the tool. The anchoring function must shift from one set of slips and cooperative expander surface to the other set of slips and cooperative expander surface when the direction of the higher pressure changes. Moreover, the differential pressure acting across the bridge plug or packer may be very substantial; thus it is necessary not only that the slip mechanism be rugged but also that it be capable of positive actuation into anchoring engagement with the well casing. It is also important and necessary to avoid costly drilling operations 3,526,277 Patented Sept. 1, 1970 P CC that the slip mechanism be readily releasable when it is desired to release the anchor means so that the bridge plug or packer may be moved to another position in the well bore or retrieved from the Well.

The present invention relates to a well packer and anchor means therefor of the type adapted to satisfy the requirements outlined above.

DESCRIPTION OF THE PRIOR ART The prior art examplifying previous well packer or bridge plug constructions having double holding slip and expander means is as follows: Scott, U.S. Pat. 3,332,494, July 25, 1967; Lewis et al., U.S. Pat. 3,158,202, Nov. 24, 1964; Baker et al., U.S. Pat. 2,806,532, Sept. 17, 1957. The Lewis et a1. patent discloses external sleeves shiftably disposed upon a packer mandrel and supporting opposing slips engageable by the opposing conical surfaces of a double faced expander, the sleeves being interconnected by friction drag springs which span the double cone. As distinguished from such external sleeves interconnected by drag springs the Scott patent shows a double ended cone expander between upper and lower sets of slips and wherein the slips are supported by a conventional friction drag device, and the upper and lower slip elements are rigidly connected by a bar welded at its ends to the respective slips and spanning the double expander. In the Baker et a1. patent the upper and lower slips are interconnected together externally of the tool mandrel between a downwardly facing cone and an upwardly facing cone respectively adapted to actuate the upper and lower slips into anchoring engagement with the casing.

SUMMARY In order to satisfy the requirements respecting ruggedness, certainty of anchoring actuation and easy troublefree release, and in order to avoid utilization of such devices as external sleeves interconnected by bow springs to support independently actuatable slips or rigid bars interconnecting slips so that such slips are not independently actuatable, as well as to avoid the relatively complex construction of opposing cones and intermediate slips, as exemplified in the prior art set forth above, the present invention provides a packer or bridge plug having an anchor mechanism which is rugged, easy to assemble, certain in its actuation and so constructed as to be troublefree in its release.

More particularly, the invention provides a well packer or bridge plug having anchoring means of the type embodying an expander. member having opposing conical expander surfaces formed as an integral part of a section of the packer mandrel and wherein sets of slip elements are interconnected together by a tie member disposed internally of the mandrel, and each of the slip elements being of the typical form of well packer slip in that it is independently actuatable and is ruggedly supported on the usual T-head. The slip subassembly, moreover, is adapted to be held stationary in the well bore as the mandrel moves longitudinally in either direction by a friction drag assembly which in itself is conventional and trouble-free.

An object of the invention is to provide a packer or bridge plug assembly which may be easily released, notwithstanding the fact that it may have been anchored in a well bore in response to severe differential pressure acting across the packer tending to forcibly set the anchor slips.

Another object of the invention is to provide an anchor subassembly comprising friction drag means, upper and lower anchor slips and an intermediate cone, adapted as a unit to be applied to a packer assembly.

Other objects and advantages of the invention will be hereinafter described or will become apparent to those skilled in the art, and the novel features of the invention will be defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. la and lb together constitute a view in longitudinal section showing a retrievable bridge plug embodying the invention and disposed in the well casing, the plug being in condition for running the plug into the wall casing, and FIG. 1b being a downward extension of FIG. 1a;

FIGS. 2a and 2b together constitute a view in longitudinal section generally corresponding to FIGS. 1a and lb but illustrating the plug anchored in the casing under the influence of high pressure above the plug;

FIG. 3 is a view in vertical section, as taken on the line 3-3 of FIG. lb; and

FIG. 4 is a view in vertical section, as taken on the line 4-4 of FIG. 2b.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. la and lb, it will be seen that the retrievable bridge plug of the present invention comprises an elongated inner member 1 threadedly connected as at 2 to an upper control head generally designated 3. Disposed about the inner member 1 is an outer member or vertically elongated body in the form of a tubular assembly generally denoted at 4 and having in axially spaced relation thereon well wall-engaging or casing wall-engaging anchor means generally denoted at 5 and located at the lower end of the tool, well wall-engaging friction means generally denoted at 6, and well wall-engaging or casing wall-engaging packing means generally denoted at 7. At the lower extremity of the outer member 4 is a bottom cap or bullnose 8 suitably secured in the open lower end of the outer member 4.

The outer tubular member or assembly 4 consists of a lower tubular body or mandrel 9 to the lower end of which is connected the nose 8, and adjacent the upper end of Which is slidably disposed a drag block cage or carrier 10 having a central opening 11 through which the body 9 extends. The cage 10 is provided with a plurality of longitudinally extended, radial slots or grooves 12 which receive a like number of radially shiftable drag blocks 13 each having outer friction surfaces .14 engageable with the well casing. The drag blocks 13 are biased into frictional engagement with the well casing by spring means which, in the illustrative example, includes a plurality of coil springs 15 acting outwardly on the drag blocks and seating against the base of the drag blockreceiving slots 12. Outward movement of the drag blocks 13 is limited by retainer rings 16 and 17 respectively located at the upper and lower ends of the drag block cage and secured thereon by means of fasteners 18 and 19, respectively.

Supported by the drag block carrier 10 is an upper set of slip elements 20 and a lower set of slip elements 21 respectively provided with upwardly facing wickers or teeth 22 and downwardly facing wickers or teeth 23 adapted, as will be hereinafter described, to be forced into engagement with the wall of the casing C. The slip elements 20 of the upper set of slips each include supporting means independently shiftably mounting the same on the lower end of the drag block carrier 10 and comprising T-heads 24 disposed in laterally opening T-slots 25 prov ded in the drag block carrier .10. The drag block retaining ring 17 is provided with circumferentially spaced end projections 17a which extend into laterally extended slots 17b in the T-heads 24 for abutting engagement by end walls 17c of the slots 17b so as to limit outward movement of the slip elements 20 and thereby maintain the same in assembly with the drag block carrier 10. If desired, the slip elements 20 may be resiliently retained in inner positions by a suitable garter spring 26 or other confining spring means, such as a rubber O-ring.

The slip elements 21 of the lower set of slips are carried by a lower slip carrier ring 27 which is slidably disposed upon the tubular body or mandrel 9. This slip carrier ring 27 supports the slip elements 21 for independent lateral actuation substantially in the same manner as the upper slip elements 20 are supported by the drag block carrier 10. Thus, each of the slip elements 21 has a T-head 28 disposed in a laterally opening T-slot 29 provided in the slip carrier ring 27. A retainer ring 30 is d sposed about the slip carrier ring 27 and retained in place by suitable fasteners 31, this retainer ring 30 having circumferentially spaced end projections 30a extending into laterally opening slots 30b in the T-heads 28 and engageable with an end wall 30c of the slot 30b to limit outward movement of the slip elements 2.1. Here again, if desired, a suitable garter spring 32 or other confining means may be provided for normally holding the slip elements 21 in an inner position.

As best seen in FIGS. 3 and 4, in order to interconnect the drag block carrier 10 with the slip carrier ring 27 so that the upper and lower slip elements 20 and 21 cannot move longitudinally with respect to each other a reduced diameter inner mandrel section 33 is provided and is slidably disposed within the tubular body or mandrel 9. Connector means in the form of an upper crossbar 34 and a lower crossbar 35 are provided for connecting the inner mandrel section 33 at its upper end to the drag block carrier 10 and at its lower end to the slip carrier ring 27. The crossbar 34 extends through complemental openings 36 in the inner mandrel 33, through vertically elongated slots 37 in the outer body or mandrel 9, and into complemental openings 39 provided in the drag block carrier 10 between an adjacent pair of the drag blocks 13. The crossbar 34 may be suitably integrated with the drag block carrier 10 and the inner mandrel 33 as by the use of retaining screws 40 threaded into the ends of the crossbar 34 and having their heads engaging in the drag block carrier 10. The crossbar 35, like the crossbar 34, extends through complemental openings 41 in the inner mandrel 33, through elongated slots 42 in the outer body or mandrel 9, and into complemental openings 43 in the slip carrier ring 27. Here again, the crossbar 35 may be integrated with the inner mandrel 33 and the slip carrier ring 27 by the use of fasteners 44 engaged in the ends of the crossbar 35 and having their heads engaged in the slip carrier ring 27. It will now be apparent that the inner mandrel 33 and the outer mandrel 9, together with the slip carrier ring 27 and the drag block carrier 10, comprise a unitized subassembly; and the elongated slots 37 and 42, through which the respective crossbars 34 and 35 extend, will permit relative longitudinal movement of the upper and lower slip elements 20 and 21 and the outer mandrel or body 9.

The anchor means 5 also includes, in addition to the upper slip elements 20 and the lower slip elements 21, an intermediate expander generally denoted at 45 and having an upwardly facing conical section 46 and a down- Wardly facing conical section 47. These conical sections 46 and 47 of the expander 45 are respectively adapted to cooperate with opposing angular surfaces 46a and 47a provided on the upper slip elements 20 and the lower slip elements 21 in such a manner that upward movement of the mandrel 9 and the expander 45 which is integral therewith relative to the friction drag means 6 will cause independent outward expansion of the slip elements 20 and downward movement of the mandrel 9 relative to the friction drag means 6 will cause independent outward expansion of the slip elements 21. In either of the just mentioned cases, the other slip elements will be free for movement towards their normal inner position; and actuation of the respective slip elements 21 or 22 has no other effect on the other slip elements than to free the latter for release from the casing wall when the slip elements engaged by the expander are expanded into anchoring engagement with the casing wall.

The subassembly comprising the outer body or mandrel 9, the friction drag means 6 and the anchor means 5 carried by the mandrel 9 also includes in the specifically illustrated embodiment a connector head 48 in the form of an elongated member disposed within the inner mandrel 33 and the upwardly extending portion of the body or mandrel 9 and having an axially extended cross slot 49 therein through which the crossbar 34 extends. At its upper end of the connector head 48 is adapted to be threadedly connected as at 48a to the lower extremity of the inner control member 1, previously referred to, whereby the control member is adapted to either move the anchor means 5 longitudinally in the well casing, with the expander 45 centralized between the slips 20 and 21, or to position the connector head at a position relative to the crossbar 34 so that the outer body 9 is free to move axially of the assembly in either direction while the friction drag means 6 holds the expander 45 stationary.

At its upper extremity, the body 9 of the outer tubular member 4 is connected as by a thread 9a to the base 50 of a valve body generally denoted 51. The base 50 has, at its upper end, a cup-like section 52 which flares outwardly and is longitudinally slotted at 53 at a plurality of circumferential locations to provide flow passages therethrough. Threaded as at 54 to, or otherwise made a part of the cup-like member 52, is a tubular packer support 55, to the upper end of which is connected as by a thread 56, or the like, an inverted cup-like member 57 provided with a plurality of circumferentially spaced slots 58 providing flow passages which communicate through the packer support 55 with the passages 53. This cup-like member 57 is formed at the lower end of an upwardly extended valve body 59.

Mounted about the packer support 55 is a pair of opposed packer cups respectively designated 61 and 62. The cup 61 has a lip portion 63 extended upwardly for engagement with the well wall, while the cup 62 has a lip 64 extended downwardly for engagement with the well wall, the lips 63 and 64 being spaced from the cup-like members 52 and 57 within the zone of the slots 53 and 58. The cup 61 is in abutment at its lower end with a gauge ring 65 disposed about the packer support 55, and the cup 62 likewise is in abutment at its upper end with a gauge ring 66, the gauge ring 65 having at its inner margin a seat 67 opposed to a similar seat 68 in gauge ring 66 for engagement with a split retainer ring 69 adapted to fit in an annular groove 70 extended about the packer support 55. This ring 69 holds the respective packer cups against longitudinal movement on the support 55.

Sealing means are also perferably provided to prevent leakage of fluid between the cups and their support 55; and such sealing means preferably includes a pair of rings 72 and 73 seating in grooves extended about the packer support 55 and engaged with the inner periphery of gauge rings 65 and 66.

Extended longitudinally through the outer tubular member 4 described above, is the elongated inner member generally denoted at 1. This inner member is a control member for use in the running and setting, as well as in the release and recovery of the well tool. The upper section of the control member 1 extends through the portion 59 of the outer member, through the packer support 55, through the base 50 of the cup-like member 52 and into the body 9.

Slidably disposed about the inner member 1 within the cup-like member 52 of the outer tubular assembly 4 is a valve head 80 normally biased upward by a coiled spring 81 toward a valve seat 82 provided at the lower end of the packer support 55. Slidable upon the inner member 1 within the cup-like member 57 of the outer tubular as sembly 4 is a valve head 83 normally biased downward by a coiled spring 84 toward a seat 85 formed at the upper end of the packer support 55. Valve is adapted to be moved oil? of its seat by means of a flange 86 formed on the inner member 1, and valve head 83 is adapted to be moved upwardly off of its seat by a flange 87 formed on the inner member 1. The spacing of the flanges 86 and 87 longitudinally of the inner member 1 is such that upon longitudinal movement of the member 1 so as to move one of the valves oiT its seat, the other valve will be allowed to move onto its seat. Hence, communication through the packer support 55 between the passages 53 and 58, that is, the ability of fluid to by-pass the packer, is controlled by the valves 80 and 83 responsive to the positioning of the inner member within the outer assembly 4.

Downward movement of the control member 1 within the outer tubular assembly 4 when these components are in a normal angular relationship is prevented by abutment of the control head 3- with the upper extremity of the outer member 59. More particularly, in reference to FIG. la, it will be noted that the member 59 is provided with a pair of elongated slots 95, and the control head 3 is provided with fingers 96 extending into the slots Extended circumferentially between the fingers 96, the control head is provided with an abutment surface 97 engageable with the end surface 98 of the outer member 59. The distance from abutment surface 97 to the upper extremity of the lost-motion slot 49 in the connector head 48 determines the relative longitudinal relationship between the body '9 of the outer tubular assembly 4 and the drag block carrier 10 and, therefore, determines the relative longitudinal relationship between the expander 45 and the slip elements 21 and 22.

Therefore, as seen in FIGS. 1a and 3, when the tool is being run into a well by weight applied to the control head 3, the contacting abutment surfaces .97 and 98 'Will cause the outer tubular assembly 4 to move downwardly along with the control member 1; and the crossbar 34 engaged at the upper end of the slot 49 in the connector head 48 will cause similar and simultaneous movement of the drag block and the slip assembly along 'with the outer tubular assembly 4. 1

However, when running-in weight is relieved from the control head 3, the force of compression spring -81 acting upwardly on valve head 80' will move the latter into a closed position on its 'seat 82 and will thereby slightly raise the inner control member. Such upward movement of the control member 1 will move the connector head 48 upwardly relative to the crossbar 34 and thus the tool will be conditioned so as to be subsequently set or anchored in the well casing upon the application of fluid pressure from above against the packer cup 61 which will close the valve '83, or pressure from below against cup 62 and the normally closed valve 80.

In the event that pressure is applied from above, as during the injection of fluid into subsurface earth formations above the location at which the packer is set, then fluid pressure will, as shown in FIGS. 2a, 2b, cause downward movement of the outer tubular assembly 4 relative to the drag block carrier 10', the drag blocks of which are frictionally engaged within the well casing; thus downward movement of the tubular assembly 4 will cause downward movement of the mandrel 9 and the expander 45 carried thereby relative to the slip elements 21 and 22 with the result that the expander cone surface 47 will engage the surfaces 47a of slips 21 to force the same into anchoring engagement with the well casing, so that the entire tool assembly will be held against downward movement. Conversely, when pressure is applied from beneath the tool, the tubular assembly 4 will be caused to move upwardly relative to the drag block carrier 10 and the expander surface 46 will engage beneath the surfaces 46a of slips 20 to cause the latter to engage the well casing and hold the entire tool assembly against upward movement.

The control head 3 is adapted to accommodate a running and retrieving tool which may be connected to a wire line or to a length of pipe, as may be desired. Accordingly, the head is herein illustrated as having at its upper end a pair of diametrically extended pins 99 adapted to be engaged in a setting and retrieving head (not shown) having appropriate bayonet-slot type means for receiving the pins 99.

In addition, means are provided for normally maintaining the inner control member 1 oriented relative to the outer tubular assembly 4 in such a position that the fingers 96 on the control head will be longitudinally aligned with the grooves 95 in the upper end of the outer tubular assembly. In the illustrative embodiment, this means in cludes an elongated torsion spring bar 100 which extends longitudinally in a bore 101 in the inner member 1 and is fixedly connected at its lower end by a coupling 102 to the inner member 1, and which is fixedly connected at its other end by a coupling 103 to the control head 3.

In order to test-set the tool when it is run into a well, the upper end of the member 59 of the outer tubular assembly 4 at one side of each of the slots 95 is provided with a circumferentially extended shoulder 104 engageable by the inner or lower end of the fingers 96 when the control member 1 is moved upwardly within the outer tubular assembly 4- and rotated, for example, one-quarter turn. In this connection, it will be understood that such upward movement of the inner control member 1 relative to the outer tubular assembly 4 is permitted by the elongated lost-motion connection slot '49. When the control head is rotated and engaged with the shoulders '4 following upward movement of the inner control member, subsequently applied downward load on the control head will be transmitted to the outer tubular body 4 without causing corresponding downward movement of the cross bar 34. Such downward movement of the body relative to the crossbar 34 and therefore relative to the drag block carrier 10, will cause the expander 45 to engage the slips 21 to anchor the tool against downward movement, thus supporting the weight of the running-in string of pipe or wire line and indicating at the earths surface that the tool is in operating condition. Such test-setting must be effected while the control head is held under torque, tending to rotate the fingers 96 to a position at which they are angularly displaced from the slots 95; and, when such torque is released, the torsion spring bar 100 will return the fingers to their normal position in alignment with the slots.

While the specific details of the invention have been herein shown and described, changes and alterations may be resorted to without departing from the spirit of the invention as defined in the appended claims.

The embodiment of the invention in which an exclusive property or privilege is claimed is defined as follows:

1. In a well bore packer, an elongated tubular mandrel, well bore wall engaging packing means on said body for forming a seal between said mandrel and the wall of the Well bore, and normally retracted anchor means carried by said mandrel and operable to anchor said mandrel against continued movement in either direction axially of said well bore, said anchor means comprising axially spaced expander means and slip means carried by said mandrel, said slip means including upwardly holding slip elements and downwardly holding slip elements, said expander means including oppositely facing cones engageable with said upwardly holding slip elements to force said upwardly holding slip elements outwardly into anchoring engagement with said well bore wall responsive to upward movement of said mandrel in said well bore and engageable with said downwardly holding slip elements to force said downwardly holding slip elements outwardly into anchoring engagement with said well bore wall responsive to downward movement of said mandrel in said well bore, tie means interconnecting one of said slip and expander means forunitary movement in opposite directions relative to the other of said slip and 0 ca expander means, control means for centralizing said expander means relative to said slip means, said tie means including an inner tubular mandrel axially extended within said first-mentioned mandrel and spanning said other of said slip and expander means, and connector means extending through 'said first-mentioned mandrel and connecting said inner mandrel to said one of said slip and expander means.

2. A well bore packer as defined in claim 1, wherein said connector means includes axially spaced crossbars, said mandrel having elongated slots through which said crossbars extend.

3. A well bore packer as defined in claim 1, wherein said control means comprises a control member extend ing longitudinally within said first-mentioned mandrel, means providing a limited lost-motion connection between said control member and said inner mandrel for limiting downward movement of said control member relative to said inner mandrel, and means on said control member and said first-mentioned mandrel for limiting downward movement of said control member in said firstmentioned mandrel to a location at which said slip means and said cone means are centralized with respect to one another.

4. A well bore packer as defined in claim 1, wherein said packing means comprises upwardly and downwardly facing packer cups carried by said first-mentioned mandrel, and said control means and said first-mentioned mandrel have valve means for allowing the flow of fluid through said first-mentioned mandrel when said slip means and said expander means are centralized, said valve means closed responsive to operation of said control means to enable anchoring of either of said upwardly holding slip elements and said downwardly holding slip elements.

5. A well bore packer as defined in claim 1, wherein said control means comprises a control member extending longitudinally within said first-mentioned mandrel. means providing a limited lost-motion connection between said control member and said inner mandrel for limiting downward movement of said control member relative to said inner mandrel, means on said control member and said first-mentioned mandrel for limiting downward movement of said control member in said first-mentioned mandrel to a location at which said slip means and said cone means are centralized with respect to one another, said packing means comprising upwardly and downwardly facing packer cups carried by said first-mentioned mandrel, and said control member and said first-mentioned mandrel having valve means for allowing the flow of fluid through said first-mentioned mandrel when said control member is at the limit of its downward movement relative to said inner mandrel and said first-mentioned mandrel.

6. A well bore packer as defined in claim 1, wherein said connector means connects said slip means to said inner mandrel, said expander means being provided on said first-mentioned mandrel between said upper and lower slip elements.

7. A well bore packer as defined in claim 1, including friction drag means connected to said one of said slip means and said expander means for preventing engagement of said expander means with either of said upwardly holding slip elements and said downwardly holding slip elements.

8. A well bore packer is defined in claim 1, wherein said connector means connects said slip means to said inner mandrel, said expander means being provided on said first-mentioned mandrel between said upper and lower slip elements, and including friction drag means connected to said slip means for preventing movement of either of said upwardly holding slip elements and said downwardly holding slip elements into engagement with said expander means.

9'. A well bore packer as defined in claim 1, wherein said slip means comprise axially spaced slip carriers slidably disposed on said first-mentioned mandrel, said upwardly holding slip elements and said downwardly holding slip elements and said slip carriers having cooperative T-head and T-slot means independently interconnecting each of said slip elements with one of said slip carriers.

10. A well bore packer as defined in claim 1, wherein said slip means comprise axially spaced slip carriers s1idably disposed on said first-mentioned mandrel, said up wardly holding slip elements and said downwardly holding slip elements and said slip carriers having cooperative T-head and T-slot means independently interconnecting each of said slip elements with one of said slip carriers, and one of said carriers being provided with friction drag block means frictionally engageable with said well bore wall.

11. A well bore packer as defined in claim 1, wherein said slip means comprise axially spaced slip carriers slidably disposed on said first-mentioned mandrel, said upwardly holding slip elements and said downwardly holding slip elements and said slip carriers having cooperative T-head and T-slot means independently interconnecting each of said slip elements with one of said slip carriers, and one of said carriers being provided with friction drag block means frictionally engageable with said well bore wall, said connector means being connected to said lastmentioned carrier.

12. An anchor assembly for well bore tools comprising: an outer longitudinally extended hollow mandrel, an inner mandrel within said outer mandrel and axially movable with respect to said outer mandrel, said outer mandrel having an expander thereon provided with oppositely facing conical expander surfaces, slip means slidably disposed about said outer mandrel and including first carrier means having upwardly holding slip elements and second carrier means having downwardly holding slip elements, said first carrier means and said second carrier means axially spaced from one another with the slip elements thereof in opposing relation to said conical expander surfaces, axially spaced connector means separately connecting said first and second carrier means to said inner mandrel, said connector means extending through said outer mandrel, whereby said inner mandrel and said slip means form a unit with respect to which said outer mandrel and said expander may move axially as a unit to selectively actuate said upwardly holding slip elements and said downwardly holding slip elements into setting disposition, means for connecting said outer mandrel to a well tool, and means for connecting said inner mandrel to said well tool.

13. An anchor assembly as defined in claim 12, wherein said outer mandrel is provided with axially elongated slots, said connector means extending through said slots, and said means for connecting said inner mandrel to said Well tool including a connector head having an axially elongated slot, one of said connector means extending through said last-mentioned slot.

14. An anchor assembly as defined in claim 12, wherein each of said carrier means is slidably disposed on said outer mandrel and including cooperative T-head and T-slot means connecting each of said slip elements to its carrier means.

15. An anchor assembly as defined in claim 12, wherein each of said carrier means is slidably disposed on said outer mandrel and including cooperative T-head and T-slot means connecting each of said slip elements to its carrier means, one of said carrier means having longitudinally extended, laterally opening slots therein, drag blocks laterally movable in said slots and means normally biasing said drag blocks outwardly with respect to said carrier for frictional engagement in said well bore.

References Cited UNITED STATES PATENTS 2,806,532 9/1957 Baker et a1 166305 3,158,202 11/1964 Lewis et al. 166-121 3,332,494 7/1967 Scott 166l21 JAMES A. LEPPINK, Primary Examiner US. Cl. X.R. 166127, 134 

